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  1. (*steve*)

    Simple LED circuit burning out

    That datasheet is fine for that LED, but not for others.
  2. (*steve*)

    Amplify signal from piezoeletric

    Here's a simple circuit for you: You are unlikely to need any voltage gain, the piezo input will be a high voltage. The 2 transistors Q1 and Q2 form a fast limiter to about ±8V. The power supply connections are not shown, but should be ±9V or greater To connect it to an arduino (analog...
  3. (*steve*)

    Particles in a Field

    Also note the strength of the field. What are the units, and what does that represent?
  4. (*steve*)

    Particles in a Field

    or use ms-1 which pretty much everyone will understand.
  5. (*steve*)

    Simple LED circuit burning out

    1/4 watt or greater. If it is possible that your resistor shorted out after you mounted it, that too could have caused the LED to fail. Heatshrink tubing over exposed wires is a good idea.
  6. (*steve*)

    help please

    Having had my hearing significantly damaged by being exposed to sound I could not hear (ultrasonic), I STRONGLY recommend that you wear hearing protection, EVEN IF YOU CAN'T HEAR ANYTHING.
  7. (*steve*)

    Whirlpool l1373 card (invensys 475560 )can't identify number for part circled inphoto can you help

    If it's marked L (as opposed to R) then it is an inductor, not a resistor. Post a photo with enough detail that we can read all the markings.
  8. (*steve*)

    (Open for advices) using the nrf52832 module MDBT42Q

    I would check to see if there is a plug-in for the Arduino ide which supports it. There are a number of similar chipsets which are. See here
  9. (*steve*)

    Now I am going to ask 3 stupid questions, please dont laugh. but i cant seem to find info

    As an interesting aside, I have an autotransformer that is designed to step down 250V to a variety of lower voltages between about 200V and 230V at 20A Part of the winding is very heavy wire, and the rest is much finer. Because it's not a variable autotransformer, only part of the winding...
  10. (*steve*)

    New guy needs help with Matco Maxme parts sourcing

    Not economical to repair. But that's never stopped me :) As long as you're not paying an hourly rate or desperate to have it fixed. If probably start by removing the USB connector so you can see where the connections are and then try to locate one that looks similar. Presumably you'll be...
  11. (*steve*)

    Multitasking with Arduino

    If you implement your functions using state machines and no delays, you can call one state machines and then the next (alternating) and you will have a useful form of multitasking. Also be aware that the atmega chip has peripherals which can be set running and left (the PWM outputs are a good...
  12. (*steve*)

    Hantek scope keeps ticking and wont turn on.

    The ticking sound is almost always due to a momentary overload followed by the protection circuit shutting down the power. (It then tries again, and again, and again...) The sound comes from the transformer. The other symptoms make it sound like a cap problem so I'd certainly start there. If...
  13. (*steve*)

    sn74f86 Wiring Help

    Assuming you have the power connected correctly, you have one input pulled high, and the other one floating high. This will give you a low output. Because the LED is connected between the output and ground, it will be off. Try connecting the input 4b to ground and explicitly connect the...
  14. (*steve*)

    New guy needs help with Matco Maxme parts sourcing

    Has this unit also gotten wet?
  15. (*steve*)

    Multi meter question?

    You need just one meter. That way you know it's correct. Once you have 2 or more you're never sure :) I have a series of high tolerance resistors (mostly 0.01% or better) that I use for checking resistance ranges, and a very accurate 10V reference (it was initially calibrated as being 7.5uV...
  16. (*steve*)

    Multi meter question?

    Oh, and the quote is "don't turn it on, take it apart"
  17. (*steve*)

    Multi meter question?

    Try replacing the batteries first.
  18. (*steve*)

    Compatible replacements for "F" version (74F244N)?

    The CMOS parts with T In their name have TTL compatible inputs. The AHT version may be the closest to a CMOS replacement for the F series TTL if you don't want to use the AS series. If it's being driven by other logic then (nose immunity aside) the outputs are generally more of an issue than...
  19. (*steve*)

    Homemade capacitors, that hold a charge?

    The number of excess (or the depletion of) electrons is very small compared with the number of electrons in the metal. The reason why they are on the surface is that the charges attract so the electrons and holes are attracted to each other. Another reason is that the electrons in excess in...
  20. (*steve*)

    Why do I get different readings from parallel-connected stopwatches?

    Aagh. A reply I thought I had posted addressed that... I considered that is the buttons are poled and debouncing is done in software, then a delay of 40ms is not unreasonable. These could easily be out of phase between multiple stopwatches.
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